Allow me to introduce myself, I race an SC400

[brawls43]

Hi, I'm Greg, I'm new to the forum here. I'm from MN and last year I built a 92 SC400 to race in the Chumpcar Worldseries. Its like 24 hrs of LeMons. We started with a twice salvaged SC400, the most recent being from hitting a bear in northern MN. So we began gutting the car, and making it race worthy.

The majority of the work can be found on our team blog, http://teambearpatrol.blogspot.com

Other then taking stuff out, our only real performance improvements were brakes, 95 LS400 front rotors and calipers, and a custom front spring set up.

At our most recent race, we began having some brake problems, so we're working to fix those, but we're also starting to look into future improvements to make. Things like what else we can delete from the engine, PCV, EGR, catalysts, etc. So I'm looking forward to digging around this site some more and finding some things to do.

 

[cribbj]

Hi Greg & welcome. Hope you enjoy your stay here and it'll benefit both sides!

There's lots of commonality between the SC and the Supra platform, so you may be able to find some relatively cheap upgrades by combining Supra, LS & SC pieces.

 

[4U2QUIK]

I'd go with the mkiv dupra brake setup, and ditch the heavy auto trans The only thing they're good for is drag racing, soaking up HP, and generating additional heat you don't need.

 

[Spinnetti]

Hey...

I checked out your blog... looks fun.. We just had our first outing at Gingerman a few weeks ago for lemons.. all worked very well, even with the stock small brakes... its all about the brake pads. What ones were you using?

 

[brawls43]

4U2quik, we wanted to do Supra brakes, but the cost of components was a lot more. It would have given us a lot more choices in terms of brake pads and rotors, but finding calipers gets pricey. The LS400 calipers I got from a yard were like $40 each.

Spinnetti, we ended up having to get custom pads made by Porterfield. They'll essentially put any pad material you want, on any backing plate you want. They had templates for the LS400 backing plate, so we didn't have to send in any used pads. We ended up getting a race pad material from Raybestos, ST43. We've gotten roughly 75 hours of racing out of them, and have pad material left. They can be load and squeaky while bedding the pads in, but they're amazing.

 

[Spinnetti]

4U2quik, we wanted to do Supra brakes, but the cost of components was a lot more. It would have given us a lot more choices in terms of brake pads and rotors, but finding calipers gets pricey. The LS400 calipers I got from a yard were like $40 each.

Spinnetti, we ended up having to get custom pads made by Porterfield. They'll essentially put any pad material you want, on any backing plate you want. They had templates for the LS400 backing plate, so we didn't have to send in any used pads. We ended up getting a race pad material from Raybestos, ST43. We've gotten roughly 75 hours of racing out of them, and have pad material left. They can be load and squeaky while bedding the pads in, but they're amazing.

Yea, I used the same ones, with porterfields hd street compound in the back- but with the stock little brakes. Will upgrade to the 95 brakes eventually. PS why did you go with so much rubber in the back? I was thinking of trying mustang 17x8 or 9 wheels, but not sure if they will fit

 

[brawls43]

We did the ST's front and rear.

For the tire, we really wanted as much on front as we could get, found some sets of used Supra TT wheels. One set (4) of all 17x8, and one staggered set (2) 17x8 and (2) 17x9.5. So we had to put something on the 9.5, and figured we'd try it out. Our suspension stiffness isn't quite right, and in some corners we spin the inner rear. So we were hoping a wider tire would help with that a little, while not causing understeer from added rear grip. It worked pretty well, last weekend was our first race with the 275's and with the Falken RT615's. We'll run a full set of 245's as comparison sometime.

 

[Spinnetti]

We did the ST's front and rear.

For the tire, we really wanted as much on front as we could get, found some sets of used Supra TT wheels. One set (4) of all 17x8, and one staggered set (2) 17x8 and (2) 17x9.5. So we had to put something on the 9.5, and figured we'd try it out. Our suspension stiffness isn't quite right, and in some corners we spin the inner rear. So we were hoping a wider tire would help with that a little, while not causing understeer from added rear grip. It worked pretty well, last weekend was our first race with the 275's and with the Falken RT615's. We'll run a full set of 245's as comparison sometime.

Sounds like we ended up with similar solutions...

Do you know the back spacing and offset of the wheels? I'm trying to figure out what all will fit - Mustang wheels are cheap, and I think might fit. I was going to try 17x8 with 245/40's

Believe it or not, the 225's are enough tire. We'll get two races out of 6 tires (with change out the left front, and RR).

You'll always spin the inner wheel with an open diff. if you weight jack it a bit to put some more load on the RR, you car reduce the wheel spin. Welded diff might be an option too.

I found too that 2nd gear is WAY too long in the LS.. (better in the SC) I got a junkyard SC300 auto diff which is good for 4.27 gears, and coupled with 225/50-16's, it gets the wheel speed up where I want it.

 

[brawls43]

Sounds like we ended up with similar solutions...

Do you know the back spacing and offset of the wheels? I'm trying to figure out what all will fit - Mustang wheels are cheap, and I think might fit. I was going to try 17x8 with 245/40's

Believe it or not, the 225's are enough tire. We'll get two races out of 6 tires (with change out the left front, and RR).

You'll always spin the inner wheel with an open diff. if you weight jack it a bit to put some more load on the RR, you car reduce the wheel spin. Welded diff might be an option too.

I found too that 2nd gear is WAY too long in the LS.. (better in the SC) I got a junkyard SC300 auto diff which is good for 4.27 gears, and coupled with 225/50-16's, it gets the wheel speed up where I want it.

I don't recall the backspacing off hand, but I know stock Mustang wheels didn't clear our 95 LS400 brakes. I had a buddy selling a set and tried. You end up needing something to clear big brake kits. Last year we ran 16" LS400 wheels with 225's and DZ101's. These lasted okay too, but we wanted more grip. We ran a set of 245/50R16 Fuzions in the fall they were a little better. So we figured getting some 245/17's would be nice too and we got more tire choices.

We thought about welding the diff, but any slow speed paddock moving would get annoying. I wish there was a cheap LSD somewhere, but even used Supra LSD's are too expensive. We're also thinking about getting the 4.27 gears like you did. Our gearing on corner exit in 2nd still isn't very good. I'm also debating a 5 speed auto swap for closer gears too. I need to research that one though.

 

[Spinnetti]

I don't recall the backspacing off hand, but I know stock Mustang wheels didn't clear our 95 LS400 brakes. I had a buddy selling a set and tried. You end up needing something to clear big brake kits. Last year we ran 16" LS400 wheels with 225's and DZ101's. These lasted okay too, but we wanted more grip. We ran a set of 245/50R16 Fuzions in the fall they were a little better. So we figured getting some 245/17's would be nice too and we got more tire choices.

We thought about welding the diff, but any slow speed paddock moving would get annoying. I wish there was a cheap LSD somewhere, but even used Supra LSD's are too expensive. We're also thinking about getting the 4.27 gears like you did. Our gearing on corner exit in 2nd still isn't very good. I'm also debating a 5 speed auto swap for closer gears too. I need to research that one though.

Lemme know what you find out on the trans swap - ECU might make that "interesting"... I think that with the gear change, we'll be right in the 2nd-3rd sweet spot, so I'm hoping we don't have to monkey with it any more than that. the 4.27 will get us out of the corners better and get in the meat of 3rd on the straights (right now, sometimes it dumps into first, then shifts back to 2nd, and its just in 3rd for a short bit before having to brake)...

 

[brawls43]

Lemme know what you find out on the trans swap - ECU might make that "interesting"... I think that with the gear change, we'll be right in the 2nd-3rd sweet spot, so I'm hoping we don't have to monkey with it any more than that. the 4.27 will get us out of the corners better and get in the meat of 3rd on the straights (right now, sometimes it dumps into first, then shifts back to 2nd, and its just in 3rd for a short bit before having to brake)...

I'm hoping its just a separate trans ECU like we have now. Otherwise I'd still like to figure out a way to control the solenoids and do more manual shifting of the trans. So are you just racing LeMons or doing any Chump? Where are you based out of again?

 

[Spinnetti]

I'm in KY. I havent run chump but may. I'd be interested to see how our cars compare on track.... There are guys who do manual shift controllers - a google should get you there. My guess/hope is that I won't even need it after the gear change. Unfortunately I have to use the whole sc diff to use the gear, and have to modify the subframe to fit it. I'm starting that this weekend. Btw, if you don't mind modding stuff, you can get the mkiii supra complete diff with LSD pretty cheap....

 

[Spinnetti]

BTW, I did finally fit the SC300 diff.. helps, but 2nd gear is still too long... Need to see if the sc trans has better ratios than LS...

 

[BlackUZZ31]

ohhh my!!! did you run wheel spacers behind the disc brake rotor???

Supra brakes are a must for the track...

 

[Spinnetti]

ohhh my!!! did you run wheel spacers behind the disc brake rotor???

Supra brakes are a must for the track...

"must for the track"? We did 17hrs with no visible rotor wear on stock early brakes.... Its all in the proper pads... I did buy some 4 piston calipers from a 95, but haven't put them on yet. I don't know if you were talking to me, but I have 1/2" spacers, but they are between the disc and the wheel, not behind the disc - that doesn't make any sense.

 

[BlackUZZ31]

"must for the track"? We did 17hrs with no visible rotor wear on stock early brakes.... Its all in the proper pads... I did buy some 4 piston calipers from a 95, but haven't put them on yet. I don't know if you were talking to me, but I have 1/2" spacers, but they are between the disc and the wheel, not behind the disc - that doesn't make any sense.

I was referring to the OP's blog that had this image:



17 hours on the stock brakes is a good effort!

maybe your track is not as hard on brakes as winton raceway

 

[Spinnetti]

I was referring to the OP's blog that had this image:



17 hours on the stock brakes is a good effort!

maybe your track is not as hard on brakes as winton raceway

IC.. yeah, those look bad.... We ran Gingerman raceway in Michigan.... its a road course and they got hot enough to stop working, but the wear on pad and rotor was practically nothing.. very impressive brake pads....